Complete genome analysis of bacteriochlorophyll a-containing Roseicitreum antarcticum ZS2-28 T reveals its adaptation to Antarctic intertidal environment

Aerobic anoxygenic phototrophic bacteria（AAPB） are photoheterotrophic prokaryotes able to use both light and dissolved organic matter as energy sources. Roseicitreum antarcticum ZS2-28 T was isolated from intertidal sediment in the Larsemann Hills, Princess Elizabeth Land, Antarctica, and was able to produce bacteriochlorophyll a. It is the type strain of the sole species within the genus Roseicitreum. The complete genome sequence of the bacterium was determined using Illumina Hi Seq X and PacBio RSII systems. The genome of R. antarcticum ZS2-28 T was 4253095 bp and consisted of one chromosome and four plasmids. A number of genes related to the bacteriochlorophyll a production, photosynthetic reaction, cold adaptation, salt adaptation, ultra-violet resistance and DNA damage repairing were found in the genome. In addition to genomic islands and type IV secretion systems, genes related to gene transfer agents were detected in the genome of R. antarcticum ZS2-28 T , suggesting that this bacterium can adapt to its environment by acquiring exogenous nucleic acids. The annotated complete genome sequence provides genetic insights into the environmental adaptation and ecological function of R. antarcticum ZS2-28 T in Antarctic coastal area.